The invention relates generally to built-in appliances, and in particular a motor vehicle car radio with an operating front capable of being removed for protection against unauthorized operation.
Removable built-in appliances are often used on modern motor vehicles and are therefore known. In order to prevent possible theft, a built-in appliance is sometimes equipped with a removable operating front which can be carried around. Without the connected operating front, operation is ruled out, so that the built-in appliance essentially loses its value. The absence of the operating front may additionally be indicated by a conspicuous warning light visible even from outside, so that a potential thief is effectively deterred from theft.
One disadvantage that has become clear in such built-in appliances is that the removable operating front is exposed to increased wear, particularly during frequent use. In this case, in particular, the sensitive electric contact points on the operating front are damaged or are soiled to such an extent that it becomes necessary to attend to the operating front regularly. The removed operating front is often not treated with the necessary care. In particular, if the operating front falls down, this results, during operation, in restricted reliability of the operating elements arranged on the operating front, with loose electric contacts being a frequent nuisance.
Therefore, there is a need for a removable built-in appliance where the reliability of the built-in appliance is not restricted even when the operating front is removed frequently. There is also a further need for a removable built-in appliance where the risk of damage to the operating front due to improper handling is reduced.
Other needs will become apparent upon a further reading of the description, taken in conjunction with the drawings.
The aforementioned needs are addressed, according to the present invention, in that an operating front for a built in appliance is designed for transmitting a mechanical actuating force to a switching point arranged on the built-in appliance. Electrical contacting of the operating front can thereby be dispensed with. Operating faults attributable to improper handling are therefore largely ruled out. At the same time, the operating front is consequently insensitive to environmental influences, for example moisture. Furthermore, the operating front can be given reduced outer dimensions because rear contact points can be avoided. Furthermore, the transmission of the mechanical actuating force to the switching point can take place both directly, for example by means of a switching mat, and indirectly, for example by means of a voltage induced contactlessly at the switching point.
The operating front may have, on its rear side facing the built-in appliance, movably guided projections which engage with corresponding contact points of the built-in appliance and thus act on the switching point. By contrast, a particularly advantageous embodiment of the invention is afforded in that the operating front is mounted movably for the purpose of transmitting the actuating force. Movable structural elements on the operating front can thereby be dispensed with, since, for actuation, the operating front is moved as a whole. In this case, in particular, guides on the operating front for actuating buttons are dispensed with, so that possible damage to a movement mechanism of the operating front is ruled out.
In this respect, it is particularly beneficial if the operating front is designed as a switching rocker. Simple force transmission can be achieved as a result, the switching rocker being formed essentially by a single component. At the same time, jamming of the operating front due to careless positioning is largely ruled out. For this purpose, the operating front is provided, for example, with recesses, by means of which the operating front engages into projections arranged on the built-in appliance.
Another particularly advantageous embodiment of the invention is also afforded in that the operating front is designed for transmitting the mechanical actuating force to a tappet connected to the switching point. It thereby becomes possible to equip the operating front with a multiplicity of actuating faces which in each case act by means of the tappet on their own switching point. Different functions can therefore by combined in an expedient way on the operating front and operating thus made easier.
Another particularly advantageous development of the invention is also afforded when the operating front has a receptacle designed for the positive insertion of the tappet. For this purpose, the receptacle has dimensions which are coordinated with the tappet and thus rule out the use of another operating front. The possibility of starting operation is therefore restricted to the original operating front, so that the value of the built-in appliance without the operating front to a potential thief is reduced considerably.
It is particularly useful, at the same time, if the operating front has a coding. The operation of the built-in appliance is thereby additionally dependent on the coding which, for this purpose, is determined, for example, by a magnetic field which is specific to the appliance and can be identified by a corresponding sensor of the built-in appliance.
A particularly advantageous refinement of the invention is also afforded in that the operating front is capable of being illuminated. As a result, it becomes possible for the built-in appliance to be operated without difficulty, even if there is insufficient light in the surroundings. In this case, illumination takes place, for example, by means of background illumination of a symbol or of another character assigned to the functioning of the operating front.
For this purpose, the operating front may have a contact point for supplying electric power to a light source arranged on the operating front. By contrast, a particularly simple embodiment of the invention is afforded in that the operating front has a light input point, connected to a light guide, for illumination by means of a light source arranged on the built-in appliance. As a result, electric contacting of the operating front can be dispensed with completely and the light source present on the built-in unit can be used at the same time for illuminating the operating front. For this purpose, the light input point may be integrated, for example, into a bearing point of the operating front in this case arranged movably, whilst, at the same time, sufficient light input can be achieved, irrespective of the actuating position of the operating front.
A particularly advantageous embodiment of the invention is achieved in that the operating front is fixed in its position by means of a manually actuable catch connection. As a result, on the one hand, the operating front can be fixed quickly and easily in its position of use and, on the other hand, it is necessary merely to actuate the catch connection in order to remove the operating front. For this purpose, the catch connection may have, for example, a displaceable bolt that is movable against the return force of a spring and is capable of being triggered by means of pressing or sliding actuation.
A particularly beneficial development of the invention is afforded in that the built-in appliance has a guide making it easier to position the operating front, the operating front having recesses and the built-in appliance having projections engaging into the latter. It thereby becomes considerably easier to handle the operating front. In particular, the guide may have a bevel or a chamfer, by means of which the operating front is guided into the correct position. For fixing, the operating front can be laid against the built-in appliance merely on one side and subsequently be fixed by means of a pivoting movement, during which the guide at the same time prevents it from possibly sliding off.